The present invention relates to an absorption-type refrigeration system with thermal energy recovery, particularly for vehicles provided with an internal combustion engine.
In order to cool the air for example in vehicle passenger compartments and the like, air-conditioning apparatus are used which operate on a thermodynamic heat transfer cycle using energy.
Usually, such air-conditioning apparatus employ a refrigeration system comprising a compressor which draws in a refrigerant fluid from an evaporator in which the fluid absorbs heat from the external environment, and compresses it to a pressure at which its boiling point exceeds the temperature of the water and air which receive the heat expelled by the circuit in a condenser, this latter being connected to the evaporator through a pressure reduction valve which causes the fluid to undergo the required pressure drop.
However, the operation of the compressor requires a considerable absorption of mechanical energy, so substantially penalising the engine and the vehicle performance, this operation moreover having to be effected through transmission members which often present constructional or operational difficulties.
Furthermore, the systems of the described type operate under high pressure conditions, and the heat exchangers used by them are therefore of considerable weight and complex construction.
There is a further cooling requirement in the case of supercharged engines, in which a substantial efficiency increase is obtained if the compressed combustion air is at low temperature.
There is therefore a requirement for a cooling system which can be used both for the internal air-conditioning of the vehicle and for cooling the engine supercharging air, and which is operated by a member which works by recovering the thermal energy dissipated by the engine without penalising the engine performance, the operation being at low pressure with the result that heat exchangers of reduced weight and cost are sufficient.
Accordingly, a primary purpose of this invention is to provide a new and improved absorption-type refrigeration system which accomplishes that purpose.
In this regard, prior known air conditioning apparatus and/or refrigerators of the absorption-type require great volumes for a vapour generator and for an absorber, with respect to the remainder of the circuit, for correct operation of the system. Accordingly, if a prior known absorption-type air conditioner or refrigerator is subjected to continuous movements, the large quantitities of liquid contained in the generator and absorber are subjected to shaking as a result of movements of the air conditioning or refrigerator system. As a consequence of this shaking, a part of the absorbing fluid starts to circulate in the circuit designed for the refrigerating fluid, and vice versa, with a consequent inversion of the system operation cycle. Thus, conventional absorption-type air conditioning apparatus and refrigerators must operate in the absence of movements, and can not be installed aboard a motor vehicle, because a vehicle, when in motion, is subjected to various movements, such as transversal accelerations (centrifugal force in curves), longitudinal accelerations (acceleration and braking in a straight course) and vertical accelerations (slope changes and bumps in the road). Accordingly, a primary purpose of this invention, as noted previously, is to provide a new and improved absorption-type air conditioning or refrigeration system, which overcomes these problems and which can be used in a motor vehicle.